Nature

A nature is something's "what-ness", secondary
substance, essence,
sort, or kind, which can be held by different things (some
separable and some inseparable).
Without one's nature, one could not exist. One's nature is the
most basic thing that can be said about something. If the nature
allows for change or growth, then one's nature stays with itself
throughout each of its stages of development. For example, an acorn
and an oak tree are two different stages of development within the
nature of "oak-ness". Humans, for example, may go from, say, a
zygote, embryo, fetus, infant, child, teenager, adult while
remaining human throughout. This shows that whatever is attained
through an exercise of free agency is not one's nature.
Jesus in Christian categories has
two natures simultaneously -
eternally divine and as of two thousand years ago, human.